Friction-induced in-situ formation of organo-fluorides

ABSTRACT

A method for forming in-situ a fluorinated organic compound or polymer film from the friction-induced reaction of an organic material, such as zinc dialkyldithiophosphate (ZDDP), and a fluoridated material, such as iron fluoride (FeF 3 ) on or in proximity to a wear surface substrate. Also disclosed is a method for producing a lubricated wear surface by frictionally reacting an organic material and a fluoridated material near a wear surface, where the reaction product is a fluorinated organic compound bonded to the wear surface.

TECHNICAL FIELD

The present application relates to the preparation of fluorinated organic material. More specifically, the invention relates to the preparation of fluorinated organic material resulting from the friction-induced reaction of fluoride material with organic material.

BACKGROUND

It is known that fluoride material such as fluorinated organic compounds (CF_(x)) in the presence of heat and/or friction on a metal surface can create new compositions on the surface, such as metal fluorides (MF). This can be illustrated as:

This reaction may provide a wear-protected surface. In one example, the fluorinated organic compound to be reacted may be Teflon® or polytetrafluoroethylene (PTFE). When added to, for example, a lubricant medium such as oil or grease, under heat and friction on a metal surface, the PTFE can be caused to chemically bond to the surface and protect the surface from wear. In these known methods, fluorinated organic compounds are always added to the metal surface to provide lubrication.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a method for providing lubrication to a wear surface. A friction-induced in-situ reaction is used to generate an organo-fluoride material with anti-wear properties. The reactants may include fluoridated compounds such as metal fluorides, boron fluorides, silicon fluorides, and other non-metal fluoride moieties. The fluoridated compounds may be used alone or in combination and are reacted with an organic compound such as zinc dialkyldithiophosphate (ZDDP) or graphite.

In other embodiments of the invention, organo-fluoride material formed by reacting fluoridated compounds with an organic compound may be bonded to a wear surface as a friction-induced reaction progresses.

In yet another embodiment of the invention, a friction-driven reaction may be used to make a material with lubricating properties. In this embodiment, a suitable reaction medium such as a base oil is chosen. A friction-induced reaction between an organic compound and a fluoridated compound generates an organo-fluoride as the reaction product. The reaction product enhances the lubricating properties of the base oil in this embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-3 are X-ray photoelectron spectroscopy (XPS) spectra showing the presence of organo-fluoride on worn surfaces.

DETAILED DESCRIPTION

A method disclosed herein forms a lubricated wear surface as one embodiment. A fluorinated organic compound or polymer (CF,) produced in an in-situ friction-induced reaction of small particles or molecules of a fluorinated compound with an organic compound, such as, for example, zinc dialkyldithiophosphate (ZDDP) or graphite. Organic compounds with weakly bonded alkyl and aryl groups are particularly suited for use in the present invention. The fluorinated organic compound forms on and/or in proximity to contact surfaces during friction and wear. In some embodiments, the fluorinated organic material works as a low-friction and wear-resistant film. The use of a metal fluoride, such as FeF₃, with ZDDP creates fluorinated organic compounds that provide better lubrication than ZDDP alone can provide on the wear surface.

The in-situ chemical reaction occurs with varieties of metal fluorides or other fluorine-containing species under a range of temperatures, contact stresses and relative speeds. This technology can be used in many different applications, such as in lubricants for automobile and aircraft engines or in other applications using moving components in need of lubrication. The method disclosed herein provides a novel means to alter the surface composition of metal, ceramics, plastics and the like through a friction-induced chemical reaction that produces functionally improved surface performance for industrial, commercial, domestic and other purposes. The invention may also be used to provide a desirable low-friction hydrophobic coating for some applications.

It has been demonstrated in friction and wear tests that exposing fluoridated compounds such as metal fluorides (MF) in the presence of organics, such as ZDDP, to heat, friction and/or wear on a metal surface will produce fluorinated organic compounds (CF_(x)) on the wear surface. This reaction can be illustrated as:

The metal fluorides that may be used with the invention include, for example, iron fluoride, titanium fluoride, aluminum fluoride, tungsten fluoride, and combinations of various metal fluorides. The metal fluoride is consumed during the reaction, unlike a catalyst. The metal fluoride may retain some catalytic functions in some embodiments. Embodiments of the invention may employ other compounds such as boron fluorides, silicon fluorides, and other non-metal fluoride moieties. Below is a specific example using iron trifluoride (FeF₃), which is converted to the difluoride moiety as the reaction progresses.

In this example, the ZDDP reacts with the iron trifluoride under friction and wear conditions and is converted into a fluorinated organic material on the wear surface, such as the metal surface of an engine. This reaction has been observed to occur with the same results at varying loading pressures. The reaction illustrated above is not a normal degradation of the organic material (ZDDP). Instead, the iron tri-fluoride (FeF₃) is consumed by the reaction with the organic material (ZDDP). The benefit of this reaction is that fluorinated organic materials are known lubricants, so the creation of fluorinated organic compounds on the wear surface provides thermal protection, wear resistance and lubrication directly at the point of highest need. In some embodiments, the wear surface material may be chosen to catalyze the reaction of the fluoride-containing material and the organic compound.

It will be understood that other fluorine-containing compounds may be used in place of or in addition to ferric fluoride (FeF₃), including, for example, aluminum trifluoride (AlF₃), cryolite (Na₃AlF₆), zirconium tetrafluoride (ZrF₄), titanium trifluoride (TiF₃), titanium tetrafluoride (TiF₄), tin fluoride (SnF₂ and SnF₄) and the like, and combinations thereof. Transition metal fluorides are used in certain embodiments. It will be further understood that a wide range of other organics may be used in place of ZDDP. Select inorganic compounds may be used in some embodiments, such as, for example, boron- or silicon-containing compounds.

In the above-illustrated reaction, the MF and organics react under friction and/or heat to create new materials, fluorinated organic materials, that are known lubricants. In an exemplary embodiment, no fluorinated organic materials are present at the beginning of the reaction. However, in the presence of heat and/or friction during wear, fluorinated organic compounds are formed and act as a lubricant on the wear surface. In other embodiments, fluorinated organic compounds that have poor or no lubricant properties may be present at the beginning of the reaction and, in the presence of metal fluorides, these non-lubricant fluorinated organic compounds react under heat and friction to create other fluorinated organic materials that are good lubricants and wear-reducing agents. In some embodiments, heat is not required for reaction progression, and may occur at ambient temperatures and pressure. The use of a metal fluoride, such as FeF₃, with ZDDP creates fluorinated organic compounds that provide better lubrication and wear protection than ZDDP alone can provide on the wear surface.

The reactants may be brought into contact by dissolving them in an appropriate solvent or medium. Certain reactants may be in particle form and may be prepared for the reaction by generating a suspension of those particles. The particle size may vary in embodiments of the invention, but are sub-micron in size in a preferred embodiment. The fluorinated reactant compound is usually provided in a particle form, but the organic reactant compound may also be in particle form in some embodiments.

The beneficial results of the present invention may be demonstrated by friction and wear tests using, for example, a ball-on-ring unidirectional sliding type Plint machine. FIGS. 1-3 illustrate results of friction and wear tests that were conducted at approximately 25° C. for a range of contact pressures for iron fluoride (FeF₃) in combination with ZDDP. No organo-fluorides were present at the start of the test. The spectra of FIGS. 1-3 are XPS analyses of wear surfaces for ball surface pressures of 2.32, 2.93 and 3.68 GPa, respectively.

Two distinct F1s peaks appear in each FIGURE. The peaks that at approximately 690 eV (101, 201, 301) are identified as fluorine bound to carbon, as found in fluorinated organic materials, CF_(n) (where n≧1). The peak at about 685.5 eV is identified as F bound to a metal, such as FeF₃. The organo-fluorides (CF_(n)) form in-situ on the wear surface and help to protect the surface from further wearing. Because no fluorinate organic compounds were present at the beginning of the wear test, it is apparent that the CF_(n) is created from the interaction of the ZDDP and FeF₃ on or near the metal surface. No fluorinated organic compounds are observed by conducting the same tests without ZDDP present.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps. 

1. A method for providing lubrication and wear protection to a wear surface comprising: providing a fluorinated material and an organic material proximal to a wear surface; and forming an fluorinated organic compound in contact with the wear surface by friction-induced reaction of the fluorinated material with the organic material.
 2. The method of claim 1 wherein the fluorinated material is a metal fluoride.
 3. The method of claim 1 wherein the wear surface is a catalyst for said step of forming a fluorinated organic compound.
 4. The method of claim 1 wherein the fluorinated material is selected from the group consisting of: ferric fluoride (FeF₃), aluminum trifluoride (AlF₃), cryolite (Na₃AlF₆), zirconium tetrafluoride (ZrF₄), titanium trifluoride (TiF₃), titanium tetrafluoride (TiF₄), tin fluoride (SnF₂ and SnF₄), transition metal fluorides, and combinations thereof.
 5. The method of claim 1 wherein the organic material is selected from the group consisting of: zinc dialkyldithiophosphate (ZDDP), graphite, dialkyldithiophosphate, organic compounds with weakly bonded alkyl and aryl groups, and combinations thereof.
 6. The method of claim 1 wherein the wear surface is selected from the group consisting of: metal, ceramic, plastic, glass, wood, mineral, and combinations thereof.
 7. The method of claim 1 wherein the wear surface is a substrate for said friction-induced reaction.
 8. The method of claim 1, wherein said fluorinated organic compound is bonded to said wear surface.
 9. The method of claim 8, wherein said fluorinated organic compound is a polymer film weakly bonded to said wear surface.
 10. The method of claim 1, wherein said fluorinated material is in particle form.
 11. A method of manufacturing a lubricant comprising: adding a fluorinated material to a base oil; adding an organic material to the base oil; and frictionally reacting in-situ the fluorinated material and the organic material to form a fluorinated organic compound.
 12. The method of claim 11 wherein the fluorinated material is selected from the group consisting of: ferric fluoride (FeF₃), aluminum trifluoride (AlF₃), cryolite (Na₃AlF₆), zirconium tetrafluoride (ZrF₄), titanium trifluoride (TiF₃), titanium tetrafluoride (TiF₄), tin fluoride (SnF₂ and SnF₄), transition metal fluorides, and combinations thereof.
 13. The method of claim 11 wherein the organic material is selected from the group consisting of: zinc dialkyldithiophosphate (ZDDP), graphite, dialkyldithiophosphate, organic compounds with weakly bonded alkyl and aryl groups, and combinations thereof.
 14. An engine oil produced according to the method of claim
 11. 15. The method of claim 11, wherein the fluorinated material is a particulate.
 16. The method of claim 11, wherein the base oil is selected from the group consisting of: mineral oil, hydrocarbon oil, grease, light oil, synthetic oil, polymer oil, and combinations thereof.
 17. A method for producing a lubricated wear surface comprising the steps of: providing a wear surface; providing a fluorinated material and an organic material proximal to the wear surface; reacting the fluorinated material with the organic material by exposing the fluorinated material and organic material to wear surface friction by-products and forming a fluorinated organic compound bonded to said wear surface.
 18. The method of claim 17 wherein the fluorinated material is selected from the group consisting of: ferric fluoride (FeF₃), aluminum trifluoride (AlF₃), cryolite (Na₃AlF₆), zirconium tetrafluoride (ZrF₄), titanium trifluoride (TiF₃), titanium tetrafluoride (TiF₄), tin fluoride (SnF₂ and SnF₄), transition metal fluorides, and combinations thereof.
 19. The method of claim 17 wherein the organic material is selected from the group consisting of: zinc dialkyldithiophosphate (ZDDP), graphite, dialkyldithiophosphate, organic compounds with weakly bonded alkyl and aryl groups, and combinations thereof.
 20. The method of claim 17 wherein the fluorinated organic compound is a polymer film weakly bonded to said wear surface. 